GUI Differential Equation Solver on Qt

This is a GUI based Differential Solver made on Qt (pronounced “cute”). I learned to use Qt here.

It solves second order differential equations of the form y’‘=f(y’,y,t), given a start and end time, and initial conditions on y and y’. The algorithm used to solve the differential equation is the Euler method, which is only a first-order method. Improvements can be made to this without too much difficulty to increase the order (and accuracy).

To use this GUI, simply install Qt, create a new project and add the files from this folder into your project. It should look something like this:

On runnning the project, you will get this window:

Now all you have to do is to enter the expression for y’’ (write the expression just as you would enter in a calculator; remember to write 2*y instead of 2y, and so on), the time range, and the initial values of y and y’. Click on the Evaluate button and wait for a few seconds. The plot of y versus t will be displayed.

Here is an example: For the equation y’‘=y’-3y, with t from 0 to 10, and initial conditions y(0)=0, y’(0)=1:


Almost all the relevant code is in diff_solver.cpp. In case the layout of the window doesn’t suit your fancy, you can change the positioning of the text boxes, plot and button either in the code in diff_solver.ui, or directly, in a much easier way, through the GUI preview that can be seen on clicking diff_solver.ui in the left pane in Qt.